As is explained, for example, in commonly assigned U.S. Pat. No. 6,076,654 (Leidy) and U.S. Pat. No. 6,241,448 B1 (Nicholas), the disclosure of each of which is incorporated by reference herein, or as is otherwise known, most glass containers are manufactured by a machine type known as an I.S. machine. Containers are manufactured by an I.S. machine at one or another of a multitude of machine sections, typically, 6, 8, 10 or even 12 sections, and typically 2, 3 or 4 containers simultaneously at each machine section, depending on container size and desired production rate. As a final step in the manufacture of containers by an I.S. machine, hot containers are transferred, in unison where 2 or more containers are simultaneously manufactured at a machine section, from open blow molds of the machine section in which they were formed to a nearby deadplate of the machine to permit the blown containers to partly cool before the containers are transferred to a removal conveyor for further processing.
Typically, containers are transferred from an I.S. machine section blow mold station to a deadplate by a takeout mechanism that employs a multitude of individual takeout heads extending from an arm, one such head for each container to be transferred from the machine section. After grasping of the containers by the takeout heads, the arm of the takeout mechanism from which the heads are supported is turned by approximately 180° while the containers remain suspended from the heads, to position the containers over the I.S. machine deadplate. The takeout heads then release the containers to remain on the deadplate, and the arm of the takeout mechanism is then reverted by 180° to begin a repeat of the operating cycle, when the next glass container or set of containers manufactured at the machine section is ready to be transferred.
To minimize motion of the freshly-formed glass containers during transfer, the oscillating arm of the takeout mechanism, from which the container-carrying heads or tongues are suspended, has a parallel motion mechanism to permit the containers to remain suspended from the takeout mechanism during oscillation of the head-carrying arm of the mechanism. U.S. Pat. No. 4,494,973 (Perry), which was assigned to a predecessor of the assignee of this application, the disclosure of which is also incorporated by reference herein, describes an I.S. machine oscillating takeout mechanism with a parallel motion mechanism to permit suspended containers to remain with their parallel axes vertical throughout the motion from the machine blow molds to the machine deadplate.
The parallel linkage mechanisms that are widely used in commercial I.S. machines typically use a reinforced (steel or Kevlar) Gates Rubber Seal Poly Chain GT Drive to act as a four bar linkage so that spaced, parallel shafts of the oscillating takeout arm maintain the same angular orientation through oscillation of the takeout arm about an axis of one of the shafts. This mechanism superceded chain driven parallel motion mechanisms, such as that of the aforesaid '973 patent, because chain driven mechanisms were more subject to wear than the belt driven mechanisms that replaced them. However, the belt driven mechanism of the type widely used has a maximum temperature rating of 185° F., and in a high temperature environment of an I.S. glass container forming machine, the temperature to which such a belt can be exposed can often exceed that temperature, possibly reaching a temperature of 225° F.–275° F., where the drive belt is much less strong than at its rated temperature.
Since the introduction of reinforced belt or chain driven parallel motion mechanisms of the aforesaid character, I.S. machine speeds have increased to permit greater I.S. machine production rates. These increased machine speeds require shorter container transfer times, with more precise control of acceleration and deceleration motions and with zero or near zero backlash in the operation of the oscillating takeout arm, and these added requirements have been difficult to achieve with reinforced belt or chain driven parallel motion mechanisms. What is needed, then, is a parallel motion drive mechanism that can be operated for extended periods of time in a high temperature environment, such as that near an I.S. machine, and can be operated for extended periods with minimal backlash, notwithstanding normal wear that will occur in the elements of the drive mechanism.